Effectiveness of CO₂-mediated pyrolysis for the treatment of biodegradable plastics: A case study of polybutylene adipate terephthalate/polylactic acid mulch film

Soosan KIM, Wooyoung YANG, Hee Sue LEE, Yiu Fai TSANG, Jechan LEE

Research output: Contribution to journalArticlespeer-review

Abstract

Despite the widespread use of biodegradable mulch films, they are often unsuitable for disposal in open environments and cannot be recycled in the same manner as conventional plastics; hence, an effective disposal method needs to be suggested. Herein, pyrolysis of biodegradable mulch film made of polybutylene adipate terephthalate (PBAT) and polylactic acid (PLA) was considered. The pyrolysis of the PBAT/PLA mulch film in CO₂ yielded more non-condensable gases than the pyrolysis in N₂ due to an enhanced thermal cracking of volatiles at 800 °C. At higher than 600 °C in CO₂, reverse water-gas shift reaction considerably increased CO selectivity. Using CO₂ in the pyrolysis suppressed the generation of wax and char, attributed to CO₂ enhancing not only thermal cleavage of pyrolytic volatiles released from the PBAT/PLA mulch film but also O–H and C–H bonds existing on the substance. The CO₂ pyrolysis agent forwarded the cleavage of the polymeric bond of PBAT to produce more monomeric compounds (e.g., adipates and phthalates), while it suppressed radical reactions to produce less polycyclic compounds and phenyls. Rising temperature raised the gaseous pyrolyzate yield and lowered the char and wax yields. The use of CO₂ agents in pyrolysis has a significant feature of upcycling biodegradable plastic wastes. Copyright © 2022 Elsevier Ltd. All rights reserved.
Original languageEnglish
Article number133763
JournalJournal of Cleaner Production
Volume372
Early online date28 Aug 2022
DOIs
Publication statusE-pub ahead of print - 28 Aug 2022

Citation

Kim, S., Yang, W., Lee, H. S., Tsang, Y. F., & Lee, J. (2022). Effectiveness of CO₂-mediated pyrolysis for the treatment of biodegradable plastics: A case study of polybutylene adipate terephthalate/polylactic acid mulch film. Journal of Cleaner Production, 372. Retrieved from https://doi.org/10.1016/j.jclepro.2022.133763

Keywords

  • Bioplastic
  • CO₂ utilization
  • Plastic waste
  • Thermochemical process
  • Waste treatment

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